Toxic gases used for semiconductor processing and other industrial purposes must be stored and used in accordance with strict regulations. Laws recently enacted in most states require that toxic gases be stored and delivered in lines or vessels that have at least two levels, or layers, of containment. The second containment layer protects people from exposure to the toxic gases in the case of an accident or leak affecting the first containment layer. For example, gas lines carrying toxic gases commonly consist of co-axial tubing. The gas flows through the inner tubing; the outer tubing provides extra containment in case there is a leak in the inner tubing. Gas storage and delivery systems having two containment layers are commonly called "double containment" systems.
Semiconductor manufacturers have had difficulty complying with the new toxic gas containment laws in an efficient manner because semiconductor manufacturing facilities vary widely in size, configuration and purpose. A double containment system that works well in one fabrication facility may not be useful at all in another facility. Companies, therefore, have had to develop a wide variety of double containment gas storage and delivery systems customized to accommodate the unique requirements of the various semiconductor manufacturing facilities throughout the United States. Development of such custom double containment systems is costly, inefficient, and time consuming.
In this regard, prior to the development of the present invention, no standard product was available to provide double-containment for a wide variety of possible configurations of gas delivery components, such as valves, gas lines, regulators and gauges, used in toxic gas delivery systems. Double containment boxes enclosing such components had to be designed on a "one-off" basis to accommodate the particular gas delivery components and the number of gas lines required for each specific application. As a result, engineering and design efforts were duplicated every time a new containment box was needed. Moreover, prior art boxes generally were not designed to be modifiable or moveable in any way. Thus, if the user wanted to change a component or move the box, he was unable to utilize the existing box without extensive modifications.
Additionally, gas lines are commonly connected to each other and to other gas delivery components by welding the joints. Movement of gas containment boxes and/or replacement of gas delivery components, therefore, commonly requires welding. Welding inside a fabrication facility can cause contamination problems and is often difficult to accomplish when space is confined.
Finally, most conventional gas containment boxes are designed to be wall-mounted. In many cases, the size of the fabrication facility is limited and wall space could be better utilized. For this reason, it would be desirable to set the boxes in the floor to make better use of available wall space. Unfortunately, conventional wall-mounted boxes generally are not suitable to be set in the floor without extensive customization.
Many of the problems described above are also applicable to gas containment/delivery systems in which double containment is unnecessary. For example, while there is no need for double containment for containment/delivery systems for inert, nontoxic gases, such systems suffer from the same problems of difficult customization described above.
Accordingly, there is a need for improved gas containment and delivery systems that eliminate or reduce disadvantages associated with the prior art.